Tenon-grooving machine



Aug'. 24 1926. 1,597,535'

F. J. MURDOCK TENON GROOVI'NG MACHINE Filed July 17. 1925 2 Sheets-Sheet 2 Patented Aug. 24, 1926, r i

FRED J'. MURDOCK, OF STATESVILLE, NOR-TH CAROLINA.

TENON-GROOVING MACHINE.

`-`` Application filed July 17, 1925. Serial No. 44,196.

In various localities, the manufacture of what are known as old time home-made chairs has reached the stage of a substantial industry. Such chairs are made from timber while green, and the rungs are provided with tenons which are circularly grooved or recessed after the rungs have' securely about thevtenons and prevent separation of the parts, thereby rendering the construction of the chair more durable.

Hence, it is a purpose of this invention to provide an improved cutter head of double or compound construction whereby the tenons on both ends of the rung or similar part of the chair may be made simultaneously.

Another purpose is to provide means whereby the cutters on the cutter head can be adjusted for regulating the depth ofthe grooves or channels around the rungs, whereby the securement of the. tenons in the ,ca-vities or boresof the legs or posts can be assured.

In constructing the tenons with the grooves by means of the particular arrangement of cutter heads, it is the aim to eliminate t-he use of glue 'or other fastening ieans when securing the tenons in the bores or cavities of the posts kor legs.

Still another purpose is to provide lopposed correspondingly constructed cutterv heads which support a. rung between the endsV of the cutter head, and in the operation the cutter heads form the necessary grooves or channelsv in the tenons, the ends of the tenons being of such a size as to require the forcing or hammering of the tenons into the bores or cavities of the posts or legs of the K chair, thereby dispensing with glue or the like when a rung is connected to a post or leg.

Heretofore, all tenons on chair rung con` struction have been cut either on a hard lathe or aback knife lathe which is very slow and uncertain in operation and this method has been found impractical to a certain degree.

'A further purpose is to provide a double or compound cutter head to facilitatethel manufacture of 'what is known as oid timeV home-made chairs, dispensing with the hard or back vknife lathe, saving expense in such manufacture, and to provide an improved cutter 'head which may be manufactured at small expense and sold at a reasonable prot.

It is to be understood that the particulars herein given are in no way limitative andV Figure l is a view in side elevation of k an improved double or vcompound cutter head constructed in accordance with the invention.

Figure 2 is a longitudinal sectional view through the same.

Figure 3 is a kface view of one of the cutter heads, showing the means for grooving or channeling the. surface of the tenon.`

Figure i is a sectional view on line 4e-4 of Figure y2. Y

Figure 5 is a detail view showing the cutter in elevation and the grooved tenon yin section.

Referring to the drawings, l designates a spindle, it being understood that the spindles and the other construction of both cutter heads are the same in both instances. The spindle at one end is mounted in a bearing 2 and carries a pulley 3. Each spindle passes through the sleeve 4 on which a belt pulley 5 is mounted. The pulley 3 is sedrawings and cured to the spindle by means of set-screws G so that the die.

The belt pulley 5 is shiftable on the sleeve by a ring 7 located in a space between a pulley will rotate with the spincollar 8 and the shoulder 9 caused to bel formed by the pulley. The pulley 5 lhas a frictional clutch face or depression l0 with which the frictionalface of a clutch member l1 engages, whereby whenl the pulley 5 is shifted so that the two clutch faces engage, the pulley and the clutch 11 rotate as one body. y v

A pair of belts for each cutter head are emjloyed. .These belt-sf i'espectivel f engage with the pulleys and while the. are,

in turn, designed to engage` an Overhead single pulley (not shown). It will be noted that the pulley is kof less diameter than the pulley 3 and being that the two belts are operated through a unitary rotating member, the pulley 5 will rotate faster than the pulley 3, the purpose of which'v will hereinafter appear.

The sleeve 4 is operable in a bearing 12, and secured tothe sleeve by means of setscrews 12-a is a cutter head y13.l One face of the cutter head is bored yor recessed out,

-, rotated through the medium :of Vthe clutch v providing a cavity 14 for the .reception of the auxiliary vhead 15 whichis secured by set-screws or the like 16 to one end of the spindle. The auxiliary head 15 operates in the main head 13. -Mounted KAon one end of the spindle is a` center Hand also concen-. tric with the center is a centering pin 18 with the projecting point of vwhich the end of the chair rung engages to hold the chair rung concentric withthe center of the cutter head.

Pivotally mounted upon the auxiliary head, asiat 19, are oscillatory arms 2O which carry cutters 21. The cutters are mounted andrguided in recesses 22 ofthe arms and! are disposed so that the cutting edges or cutting portions, as atI V23, will form annular grooves or recesses in the tenen of a chair rung. The cutters 21 are slotted and receive bolts 24 which permit the cutters -21 to -be adjusted radially with relation .to a .chair rungvto be engaged with the points of the centering pins 18. By tightening the bolts 24 it is possible to holdthecutters in diiferent positions, whereby their cutting edges may be adjusted ,to accommodate them to the surfaces of the tenons of the parts of a chair. n

The oscillatory arms lie against projections or pins 25 which are also .carried .by the auxiliary head. The pins or projections 25 are disposedrso as to limit koscilla- -tory movement of Ithe arms in one direction and allow them to `oscillate in the ,opposite direction. The pins or projections are reversely disposed as shown. The outer extremities of the yarms' are forked, as shown .at 26, the lforks engaging y.pins 27 `which project from the flange of the head 13. A plate 28 is mounted upon the auxiliary head 1,5 and is provided with slots 29 which receive set screws 310 which are threaded into the auxiliary head.V The plate 28 has a "rejection 31 and is adapted to engage a projecting pin 32` carried .by the fiangeof thehead 13. Y

'As `previously stated, the Vpulley y5 is of less diameter thany the pulley ,3 and since the pulley 5 is carried by the sleeve 4 and 11 and since the pulley 3 4is carried bythe spindle 1, the head 13 carried by sleeve 4 will rotate faster than the auxiliary head 15 carried by spindle 1, the two pulleys 3 and 5 being rotated from an overhead drive shaft. The head 13 rotates in the direction of the arrow shown in 'Figure 3, so does the head A 15, but since the head 13 is much faster in its revoluble movement, the pins will swingthe arms 2O upon their pivots 19 and cause the projecting cutting edges or .teeth of the cutters 21 to form or cut grooves 4or channels in -the ycircumference of the tenon formed von the end of a chair rung. By adjusting` the plate 23, that is the disltance between the projection 31 and pin 32, the .depth of the cut made by the cutting ends oredges of the cutters 21 may be regui lated. In otherwords, by adjusting .the plate 28, the distance of movement of the arms 2O on their pivots 19 can be governed,

bores .or cavities in the legs or posts of xchairs or the like lwhich are still green, the

bores or cavities being substantially smaller ,than `the tenons, the walls of the bores or cavities `will tighten around and hold the tenons secure without y,any glue or other tasfftening means to lattain this result. By fastening tenons into bores or cavities of legs,

posts .for `other similar parts of a chair or other article, the tenon remains permanent and never loosens.

Though one cutter head may be employed, there are disclosed opposed cutter heads mounted upon a bed 34 having guide chanlnels 35 in which the frames 36 of both cut ter heads are guided., and the bearings 2 f and 12 las well as the legs or supports 7a of the V rings 7 sare carried by the movable frames 36, so that these parts ofthe frame move or are shifted inl order to support a chair rung :andhoperate :the clutch.

Secured to the remote ends of the bases of both Vframes 3,6, as at 37, are springs 38, there being threaded studs 3,9 carried by the legs .of the bearings 2v and projecting through the springs, so that by adjusting .tliehnuts .40 on the studs, the tension of the .springs A38 can be regulated. The springs also engage abutments 41 which are carried by'theunder parts of the bearings 2. The

function of the abutments 41 is to limit the l pressure of the springs onthe spindles to a ,certain position of the latter-that is, to relieve the vspindles l of spring pressure ex- 'cept when they are forced axially outward Vfar enough to lift the 4springs from the f-' abutments. The springs 33 engage reduced ends of the spindles 1. Attached tot-he `springs `are'flexible members 42 which ride over pulleys 42 and have at theirlower lends weights 44, the purpose being to return the frames 36 to their initial positions in engagement with the remote end shoulders .45 of the guide channels 35, in which the ribs 36et carried by the under faces of the bases channels in order to permit the chair rung to be placed in position in the forks 46. After the rung is so placed, the foot of the operator engages with a pedal 47 pivoted upon a doi-.vnward projection 48 of ther bed 34. This pedal 47 is, in turn, connected by cables 49 passing over pulleys 50 which are carried by the bed 34, the cables being, in turn, connected at 51 to the adjacent ends or" the bases of the :trames 36. The pressure upon the pedal 47 causes thetwo frames 36 to move toward each other, and since the centering pins 18 are engaged with the ends of the rung (the spindles l moving slightly at first to permit the pins to so engage the rungs) Vthe internal or auxiliary heads 15 move slightly with the spindles, but after the pins engage firmly with the ends of the rung, the spindles 1 do not move further. However, the pressure on the pedal 47 will impart movement to the frames 36 which causes the pulleys 5 to move until they engage rictionally with the clutch faces of the clutch members 11 and then, as previously stated, the external or main heads 13 move at a greater rate of speed than the internal or auxiliary heads, thereby operating the cutters.

After the tenons oit the chair rung have been grooved, pressure may be relieved upon the pedal 47 so that, through the medium of the gravitation of the weights 44, the frames or carriages 36 are returned to their initial positions, that is, in engagement with the shoulders 45 of the guide channels. The return of the frames or carriages 36 to their initial positions will cause a disengagement ot the clutch faces of the clutch member `11 and the pulley 5, and due to the spindles being still rotated through the medium of the pulleys 3, the arms 20 (which carry the cutters) are actuated to withdraw the cutting edges from engagement with the tenons of the chair rung.

This cutter head mayV be used double headed, as shown, or as a single head and in this latter case the frame 36 may be supported stationary and under such conditions the chair rung is held either in the hands or by a pair of pliers or by any other suitable means for the purpose ot preventing rotation of the rung. However, the chair rung may be supported in a fork in front of the head, so as to center the chair rung in position. rlhe operator presses it up against the centering pin 13, whereby the tenon may be grooved. Also when using the machine employing a single head, a single trame 36 may operate in a guide of a bed, still employing a foot pedal, such as shown in Figure 1, and in this case the chair rung may be supported in a fork and by applying pressure upon the pedal, the single trame 36 may be moved to cause the two clutch members 11 and 5 to engage for operating the cutters. It is obvious that a spring (not shown) may be employed in any conventional manner in lieu of the weights 44.

The invention having been set forth, what is claimed is:

1. A tenon grooving machine comprising opposed cutter heads, each consisting oil' main and auxiliary rotating heads, spindles on which the heads olf both cutter heads are mounted and provided with means 'for the sup-port of a chair rung, unitary means lor rotating the two heads of each cutter head in the same direction, means for drivinig one head at a greater rate oi speed than the other head, and channel or groove cutting` means carried by one head and operatively connected with the other head for causing the groove or channel cutting means to engage and groove the tenons of a chair rung. p

2. A-tenon grooving machine comprising opposed cutter heads, each cutter head having main and auxiliary rotating heads, means for rotating the main head ata greater rate oi speed than the auxiliary head.. means for the su Jort ot a chair rune between the two cutter heads, and groove cuttinor means carried by the auxiliary head and having` operative connection with the main head, whereby due to the increased rate oll speed of the main head the groove cutting Vmeans engages with a tenen and cuts a groove therein.

3. A tenen grooving` apparatus consisting of opposed cutter heads, each having main and auxiliary revoluble heads, means concentric with the heads for the support of a chair rung, means for rotating the main head faster than the auxiliary head, and

channel or groove cutting members movably mounted on the auxiliary head and operatively connected with the main head, whereby due to the 'raster travel of the main head, pivotal motions are imparted to the members causing their cutting portions to engage withand groove the tenons of a chair rung.

4. A tenon grooving machine comprising means for the support ot a chair rung, main and auxiliary revoluble heads, the former travelingfaster than the latter, and tenen.

grooving members movably carried by the auxiliary head and operative by the main head tor imparting .movements to the grooving members to cause them to engage andy the former seing housed in the latter, means for rotating the spindle and the sleeve in the same direction but at different speeds, whereby Vthe main head may travel faster than the auxiliary head, and groovecutting members carried by the auxiliary head and in turn connected to the main head, whereby the faster rotation of the latter Will cause movement to be imparted to the members and hence cause their groove cutting ends to engage with and groove the tenons of a chair rung.

6. A tenen igrooving machine comprising means for the support of a chair rung', main and auxiliary revoluble heads, the former traveling faster than the latter, greoving members earried by the auxiliary head and operative by the main head for imparting' movements to the members to cause cutting devices -to engage and groove the tenons of a chair rung, and means for rotating the main and auxiliary heads in ythe same direction, the construction and arrangen'ient off said rotating means Jor the rheads being such as to cause the main. head to rotate faster than theiauxiliaryhead.

T. ln a tenen grooving apparatus, the combination with a` Spindle having' means for the support of a chair rung and carrying an auxiliary head, oit a sleeve rotatable on the spindle and carrying" a main head, the former being` housed in the latter, means for rotating the spindle and the sleeve in Ithe same direction but at different speeds,

tenon Y cutter whereby the main headv may travel faster than the auxiliary head, groove cutting members Carried by the auxiliary head and in turn connected to ther main head, Whereby the faster rotation of the latter Will cause movement to be imparted to the members and hence Cause their groove cutting ends to engage With-and groove the tenons of a. Chair rung, and means for limiting the movement oi2 the groove cutting members felativ 'to the main head Jfor regulating the depth of the groove to be cut in the tenen.

S. A tenen grooving machine comprising means 'for the support oi' a lchair rung, 0pposing cutter heads with gravity means to hold them in their extreme remote normal' positions, means tor moving the cutter heads toward each other against the gravity means to vjrip the chair rung, each cutter head comprising main and auxiliary revoluble heads, the former traveling faster than the latteig'and tenen grooving members oarried vby the auxiliary head and operated by Vthe main head tor imparting movement to the members to cause themto engage and groove the tenons of a chair rung.

9. in a tenon grooving machine, a bed, opposed .cutter heads guided on the bed, gravi ty means for holding the cutter heads suli'iciently spaced topermit 'the insertion of a chair rung, means for operating the cutter heads toward each other against the gravity means to grip the'chair rung, said heads including tenon grooving means, and rotatable members carried by each outterhead operable atvditferent speeds for actuating the tenon grooving means.

ln testimony whereof he aiiixes his signature.

FRED J. MURDOCK. 

